A modified method for urea quantification, by measuring the ammonia formed by urease, used the urease-positive Helicobacter pylori in place of purified urease with a pH indicator dye, BromoCresol Purple, to provide a color change. The color formed was stable for 20 min and could be read at 588 nm for urea quantification. Using this method, urea standard curves were linear up to 8.3 mM. As there was no need for centrifugation or precipitation, the assay was developed for use with 96-well microplates.